Remove usage of Project during task execution

[liutikas]

• Replace project with injected FileOperations object
• Replace project with logger as that's the only thing used

Fixes part of GoogleCloudPlatform/appengine-plugins#997 issue

Test: existing tests pass

[vlsi]

1. Please do not use .gradle..internal.. classes
2. FileSystemOperations requires Gradle 6.0, so either the implementation should be adjusted to support Gradle 5, or someone should decide if bumping the minimal version to 6.0 was acceptable. If the minimal Gradle version is increased, then README should be updated as well to reflect the change.

[vlsi]

FileSystemOperations requires Gradle 6.0+
Recently there was a commit comparing the version with 5.5 (see #451 ), so I'm not sure if bumping the minimal version to Gradle 6.0 is generally expected from an innocent change like this

Suggested change

	abstract public FileOperations getFileOperations();
	abstract public FileSystemOperations getFileSystemOperations();

[TWiStErRob]

Don't take my usage of 5.1 as a guide :) I used the lowest possible point where the new API is available. During maintenance this makes the condition disappear faster than if it's at the point of deprecation.

A more relevant discussion might be: #450

[TWiStErRob]

So the minimum supported version is Gradle 4.0, which means this suggestion can't work.

I think the getFileOperations() needs a

// TODO use public org.gradle.api.file.FileSystemOperations once the minimum version is greater than Gradle 6.0.

but until then it's safe to use as the FileOperations API, however internal, was added in Gradle 0.9 and hasn't changed since then (for this use case).

---

Alternatively we could use some other library to do the same. e.g.

org.gradle.util.GFileUtils.deleteDirectory(appYamlExtension.getStagingDirectory());

or

org.apache.tools.ant.util.FileUtils.delete(appYamlExtension.getStagingDirectory());

or plain old Java 8 (assuming minimum supported version allows, what is the minimum Java for this plugin? Gradle 4.0 supports Java 7 minimum):

Files.walk(pathToBeDeleted)
      .sorted(Comparator.reverseOrder())
      .map(Path::toFile)
      .forEach(File::delete);

and since the .delete() just deleted the folder it's possible to just use plain appYamlExtension.getStagingDirectory().mkdir().

[vlsi]

Please do not import org.gradle.api.internal packages. Those are not meant for general use in plugin code

Suggested change

	import org.gradle.api.internal.file.FileOperations;
	import org.gradle.api.file.FileSystemOperations;

[TWiStErRob]

It's not possible to use the public API here, because it was added in Gradle 6.0 as you said.

[TWiStErRob]

This PR is almost ready. I reviewed again deeper and it looks good, googleJavaFormat is failing the build with trivial problems. I commented what needs changing/deciding to get this merged.

[TWiStErRob]

It's not possible to use the public API here, because it was added in Gradle 6.0 as you said.

[TWiStErRob]

So the minimum supported version is Gradle 4.0, which means this suggestion can't work.

I think the getFileOperations() needs a

// TODO use public org.gradle.api.file.FileSystemOperations once the minimum version is greater than Gradle 6.0.

but until then it's safe to use as the FileOperations API, however internal, was added in Gradle 0.9 and hasn't changed since then (for this use case).

---

Alternatively we could use some other library to do the same. e.g.

org.gradle.util.GFileUtils.deleteDirectory(appYamlExtension.getStagingDirectory());

or

org.apache.tools.ant.util.FileUtils.delete(appYamlExtension.getStagingDirectory());

or plain old Java 8 (assuming minimum supported version allows, what is the minimum Java for this plugin? Gradle 4.0 supports Java 7 minimum):

Files.walk(pathToBeDeleted)
      .sorted(Comparator.reverseOrder())
      .map(Path::toFile)
      .forEach(File::delete);

and since the .delete() just deleted the folder it's possible to just use plain appYamlExtension.getStagingDirectory().mkdir().

[TWiStErRob]

gradlew googleJavaFormat wants this modifier order:

Suggested change

	abstract public FileOperations getFileOperations();
	public abstract FileOperations getFileOperations();

[TWiStErRob]

gradlew googleJavaFormat found an unused import here, which makes sense since you removed the field.